Are you over 40 and spending hours each week running and cycling to ward off the middle-age spread? You might be on the wrong track. Instead of only pounding the pavement, you need to be doing some resistance training.

‘Reaching your mid-40s once meant hanging up your trainers, but now it means buying a new pair and signing up for a midlife marathon or triathlon,’ says personal trainer Matt Roberts, who has trained David Cameron and is the author of Younger, Fitter, Stronger: The Revolutionary 8-week Fitness Plan for Men.

[How to lift weights to lose body fat]

However, is all this cardio doing more harm than good to midlifers hoping to get fit?

‘Doing too much of it has a negative effect on testosterone production,’ says Roberts. ‘And that matters. As men get older, they’re effectively becoming a little bit more female as their testosterone levels decline and become out of sync with their levels of the female hormone oestrogen. So once men get into their 40s they should focus less on pounding pavements to burn off calories and more on maintaining their decreasing testosterone levels.’

Which is why, according to Roberts, those hoping to tone up their dad bods should ease off the Lycra and start lifting weights three times a week instead: ‘Lifting weights is a quicker, more efficient way to get fit and burn fat in midlife,’ he says. ‘From our mid to late 30s, we all lose muscle mass through a process known as sarcopenia. After 50, men start to lose around 500g of muscle per year, all because of decreasing testosterone levels. This reduced muscle mass results in fat gain, especially around the midriff and sides (the love handle area), the chest and stomach.’

The answer is to start lifting weights, which boosts flagging testosterone levels. ‘Weight training, strength training, resistance training – whatever you call it, it’s anything that involves lifting weights or working against a resistance: so hand-held weights in the gym, a Body Pump class, or exercises using your own body weight, like a press up, or working on a pulley or cable machine,’ says Roberts.

‘It changes you hormonally. Lifting weights can also improve your libido and bone density levels.’

The Daily Telegraph